DC motor Control questions

[blakester]

I probably am looking for 50 psi and 300L per hour ish....

 

[blakester]

3000 L/ph I mean or 750Gph

 

[bigdeano]

50 psi and 750gph figures out to .36 hp. I don't know what kind of pump you're using, but 3/4 hp would probably be enough power.

 

[LD1]

Yea, 5hp is major overkill

 

[damartin]

I read that many people needing a variable speed motor will buy a used treadmill and use the motor and controls off of it.
I thing many of the treadmills are about 2 hp and they are easy to find on Craigslist. Good luck with your project.

Dwight

 

[Handloader109]

Still, look at a vfd if you run a 3ph motor. It will both allow you to power with single phase, and allow you to vary the speed of the motor. Now a gearbox may be better, as slowing down the motor reduces the torque, hence the output.... And evilbay can be your friend for vfds

 

[jenkinsph]

3000 L/ph I mean or 750Gph

For 50 psi at 750 gallons per hour, and what are you pumping? That can make a difference too, does it need to be food grade? What is the viscosity of the liquid?

Your flow and pressure may not require much for a low viscosity liquid and a small simple pump for $150 may be all you need.

 

[evo803]

Now a gearbox may be better, as slowing down the motor reduces the torque, hence the output

I thought that an electric motor has maximum torque output at zero RPM ? I thought that is what Elon Musk said in an interview about why his Tesla P90d was so quick .

 

[Mendonsy]

[/B]

I thought that an electric motor has maximum torque output at zero RPM ? I thought that is what Elon Musk said in an interview about why his Tesla P90d was so quick .

It depends on how the motor is made, some do, some don't.

 

[Dave M7040]

Why not try and accomplish the flows and pressures you want on the fluid side.
Restricting the flow on a centrifugal pump reduces the load since there is no flow.
A globe valve on the output would give you a reasonable throttling control. Don't use a ball valve as fine tuning it is difficult.
You can also tee off some of the output and send it back to the reservoir using a valve to control how much .
Dave M7040